I'd say take any Pratchett book, open it at a random page and you have your quotation right there...^^

I actuallytried it myself right now...and here you go...it's actually a bit too long for a normal quote...but never mind...

"Lady Ramkin drawing herself up haughtily was not a sight to forget, although you could try. It was like watching continental drift in reverse as various sub-continents and islands pulled themselves together to form one massive, angry protowoman."
Terry Pratchett, Guards! Guards!

One of my alltime favourites:

Always be wary of any helpful item that weighs less than its operating manual.